This research core application describes a plan to establish a Flow Cytometry Core Facility that will support the current and future research of the multi-investigator project. The Flow Cytometry Core Facility will also serve the HSC research community, and provide a critical resource for establishing the HSC as a center of biomedical research excellence (COBRE). The Core Facility will use existing instrumentation including an analytic flow cytometer (FACScan) and a cell sorter (FACStar Plus). Funding is requested for a leser and computer upgrade for the FACStar Plus, partial salary support for a Core Director, full salary support for a Technical Director, and service contracts for both instruments. This proposal describes features of the Flow Cytometry Core Facility including the management plan, the fee structure, a description of services, the quality assurance plan, and strategies to maintain and expand the facility over the life of the project and beyond. In addition, the proposal includes a description of how the facility will enable the COBRE investigators and mentors to fulfill their research objectives.